This invention relates generally to the field of automatic processing of components and parts, and more specifically pertains to a combination drilling and tapping machining unit that is cam actuated for attaining highly precisional and effectively longitudinal shifting of the tool into operative position for performance of a machine tool function, while at the same time, the tool and its spindle are conveniently rotated by the drive means useful for actuating the cam operated machining unit.
A great variety of power operated tools with control feed mechanisms have been available in the prior art, and which incorporate various drives, whether it be the chain drive, or the like, for attaining revolving of the working tool, or the longitunal shifting of the tool during a feed operation. All of these have long been disclosed. For example, the U.S. Pat. No. 2,791,922, to Robinson, discloses a portable power operated tool wherein both rotary motion is provided for its spindle, and translatory motion is also provided for the same through the use of screw thread means that are provided exteriorly of its spindle. While this particular early tool may be effective for accomplishing rather generally the purposes for which it was designed, one of the major drawbacks in the use of such a tool is that backlash cannot be controlled through the type of drive arrangements shown, and therefore, the application of that particular design for installation within precision machine tools, where highly accurate tolerances must be met, cannot be achieved.
A positive feeding structure for both rotating and feeding tools and the like is also shown in the Quackenbush U.S. Pat. No. 3,411,385, but once again, it appears that the feed stroke is obtained through the use of the screw assembly as indicated within its structure. In such a construction, backlash, as when the changeover from one longitudinal movement of the tool to the alternative occurs, as during its application, simply cannot be avoided.
The U.S. Pat. No. 3,512,434, to Juhasz, discloses a drill means with automatic feed and quick retraction assembly, but the structure and operation of the shown device, for attaining both its rotary motion and the automatic feed and retraction movements, are obtained through its drive gear train, and not through the use of any conjugate follower system, and the appended precision that can be obtained from such a system, as is utilized in the current invention.
The U.S. Pat. No. 3,561,544, to Farmer, discloses a parallel shaft driven machine tool way or quill unit, that contains a complex series of interrelated gears for accomplishing both the advanced motions and rotation to the quill type tool driven member. And, the complex interrelationship of its gears and the incorporation of a variety of planetery and sun gears for accomplishing both of these motions, as such, normally induces a loss of precision in machine tool functions because of such an intergeared structure.
The patent Petroff, U.S. Pat. No. 3,690,782, upon a lead-screw tapping head, discloses a threading tool having an axially moveable quill and a rotatable spindle mounted bearing. The advancement of the quill is obtained through a clutch means, attached to a lead screw, in order to obtain this axial movement for the same, but that the use of a lead screw in this type of a structure not only lessens the precision that can be obtained through the operations of the device, as for example, due to backlash that may occur particularly when a precise depth of drilling is sought upon a component being worked, but at the same time, speed of both advancement and the retraction of the tool cannot be obtained from the lead screw type of mechanical means.
The U.S. Pat. No. 3,859,001, to Hoddinott, et al, discloses a quill drive mechanism for machine tools. This particular device incorporates a computer programming means for effecting a slide mounting of the quill supported spindle, in order to obtain axial movement for the latter, while the spindle also undertakes its rotation. This invention is more concerned with the electronic controls for a machine tool, rather than with the construction of the spindle mounted tool itself.
The U.S. Pat. No. 3,885,635, to Mensel, discloses a multi-speed mechanical quill spindle drive mechanism for a machine tool. The spindle of the shown device is rotated by means of the intergearing from the drive motor but that the axial movement for the spindle appears to be obtained from the screw type feed mechanism that mounts upon the surface of the spindle supported quill. Actually, the axial movement for the quill shaft is obtained through a second motor means that produces apparently the rotation for the quill to effect its movement along its threaded connection, as shown.
The patent to Turner, U.S. Pat. No. 3,955,629, discloses a mechanical quill feed unit. But, the unit as shown is one which apparently utilizes the ball-screw assembly for obtaining the rapid axial and feed movements for the quill mechanism, and which is of the type that does evidence backlash problems during its operation.
The additional patent to Turner, U.S. Pat. No. 4,123,187, appears to be very similar to the previously described Turner mechanism, and which also incorporates a lead screw for providing for the axial movement to its quill supported spindle.
Another patent to Petroff, U.S. Pat. No. 4,115,025 discloses a lead screw tapping means, just as in the earlier described Petroff patent, where the tool supported spindle is longitudinally moveable through the same drive motor that affects a turning of the spindle during its operations. It would indicate that some form of a lead screw is carried by the spindle and which is effectively rotated by the drive motor means for obtaining the axial movements for its spindle in additional to its rotational turning during its usage.
The patent to Evans, U.S. Pat. No. 4,201,271, discloses a quill drive with variable feed, wherein a quill is slideable mounted within a longitudinal bore of a support housing, but it is longitudinally positioned by a ball screw. There would not appear to be the incorporation of any cam and follower drive mechanism within this Evans aparatus for obtaining its axial movements for its shown quill.
Some of the very early patents upon cam operated drill units, or other machining units, are shown in the United States patent to Petroff, U.S. Pat. No. 3,704,957, in addition to the U.S. Pat. No. 2,576,291, to Fletcher, upon a machine for cutting glass discs. Likewise, the boring machine described in the Halenbeck, U.S. Pat. No. 1,763,964, discloses automatic machine tooling, while the use of a cam means within a drilling machine is likewise shown in the Frank, et al., U.S. Pat. No. 2,885,914. Another boring machine, for constructing piston rings, is shown in the early Cramer U.S. Pat. No. 1,946,523.
In addition to the foregoing, a boring machine incorporating a cam mechanism for obtaining its drive is shown in the Barnes, et al., U.S. Pat. No. 1,880,666, while additional patents of this category are shown in the machine tool patent to Oberhoffken U.S. Pat. No. 2,167,673. The Schroeder U.S. Pat. No. 2,321,525, discloses an electric hoist, incorporating gearing mechanism, while the early United States patent to Kingsury, U.S. Pat. No. 1,998,873 shows a fluid pressure feeding mechanism for metal working tools. The Corwin U.S. Pat. No. 1,950,597 shows an automatic drilling machine.
Linear actuator apparatus incorporating rack and pinion drives are shown in the Ovshinsky, U.S. Pat. No. 3,381,539, while another form of drilling unit, incorporating various rotational movement means therein, but having links for obtaining its longitudinal movement is shown in the U.S. Pat. No. 2,574,347 to Nelson.
One of the main features of the current invention, and that which is desirably obtained from its structure, is the ability to operate a machining unit with a high degree of precision, where tolerances are kept at a significant minimum, whereas, in the prior type of devices previously analyzed, usually tolerance limitations vary quite significantly, mainly due to the problems associated with the presence of backlash, and related type of inefficiencies that have prevailed in prior designs in relation to the type of unit analyzed herein.
It is, therefore, a principal object of this invention to provide a cam operated machining unit, whereby positive mechanical synchronization of the control cam to the rotation of the spindle is incorporated to satisfy the end result of providing a pre-determined longitudinal displacement of the quill for each revolution of the continuous rotating spindle. This principal objective provides for uniform and consistent chip loading on the cutting tool which enhances cutting tool life and yields exactly mathematically defined machining times for each production utility cycle of the cam actuated unit.
Another principal object of this invention is to provide, as previously explained, a ribbed cylindrical cam for use in conjunction with the preloaded followers that provide a positive stroke control throughout the machining cycle, without any detrimental backlash being encountered.
A further object of this invention is to provide a rather cam actuated drill unit for use in conjunction with station type of machine tool processing.
Another object of this invention is to provide a cam operated machining unit that can be utilized, in combination with a plurality of such units, to achieve high production in the output of the components being manufactured.
A further and significant object of this invention is the use of a computer designed cam that incorporates a motion profile specifically selected for initiating a rapid approach toward the work station, then movement through a constant feed rate through the machining function, immediately followed by an accelerated retraction of the tool from its sites of work.
Still another object of this invention is to provide a cam actuated machining unit that incorporates full overload protection through the intergrating of electro-mechanical systems that cause clutch and brake means to disengage the unit and disable its working tool and components.
Still another object of this invention is to provide a cam operated machining unit wherein its feed means for operation of its cam is provided through a series of interrelated gears that are replaceable to provide a full range of standard operating feed ratios between approximately 42 to 1 to 1,380 to 1; there being approximately 250 different ratios within the range which can be obtained by simply changing easily these accessible quick change feed gears.
Still another object of this invention is to provide a cam operated machining apparatus that can achieve a full range of spindle speeds during unit operation.
Another object of this invention is to provide a cam operated machining unit wherein its individual spindle may be replaced by a multiple spindle tang drive for furnishing more than one machining operations from a plurality of tools all simultaneously.
Yet another object of this invention is to furnish a machining unit that is slide mounted for obtaining its quick adjustment during set up.
These and other objects will become more apparent to the skilled in the art upon reviewing the summary of this invention, and and upon undertaking a study of the description of its preferred embodiment, in view of the drawings.